118 CLASS III. 



capable, to a certain degree, of independent existence, and when 

 fully developed, separates itself from the stem of the colony (Abyla). 

 In the Prayidce, the covers are bounded by round surfaces above, 

 and have a cavity below, like a helmet, to receive the other members 

 of the group : in Diphyes they surround the stem like a rolled leaf, 

 (differing, however, in form in the different species) and adhere to 

 it by the narrow part. In Abyla they cover the members of the 

 group imperfectly, are almost solid, yet with a cavity in the interior 

 which is in connexion with that of the stem, and which is lined by 

 large cells. In all these groups the sexual buds are more or less 

 medusiform, and may be developed into a swimming bell. They 

 sprout from the base of the Polyp.] 



Comp. on this family, besides the above work of QUOY and GAIMARD, 

 especially ESCHSCHOLTZ, Syst. der Akalephen, s. 122, 123, LEUCKART Zoolo- 

 gische Untersuchungen, i. s. 41 49, KOELLIKER Die Schwimmpolyp. s. 36 

 46 : also WILL, Hone Tergestince, s. 76 83, GEGENBAUER in Zeitschr. f. 

 wiss. zool. v. s. 297 300. 



[Diphyes Cuv. The posterior swimming piece received into a 

 cavity of the anterior : the groups on the common stem protected by 

 a bract or cover in form of a rolled leaf. 



Sp. Diphyes angustata ESCHSCH. Tab. xn. fig. 6 (the species of BORY seems 

 to belong here ;) Diph. eampanulifera ESCHSCH., QUOY and GAIMARD 

 Ann. des Sc. not. X. 1827, PI. i. ; Diph. gracilis GEGENBAUER Zeitschr. fur 

 wissensch. Zoologie, v. s. 309315. Taf. xvi. fig. $>j.Diph. Sieboldei 

 KOELL. Die Siphon, v. Messina, s. 36 41. Taf. xi. fig. i 8. Diph. gra- 

 cilis GEGENB. Zeitschr. f. w. Zool. v. s. 313 315. Taf. xvi. fig. 5 7. 



Diph. Kochii WILL Hor. Tergest. Tab. 11. f. 22 26 ; figured without the 

 posterior portion which WILL did not meet with in any one of the six speci- 

 mens examined by him 1 . 



Abyla ESCHSCH. QUOY and GAIMARD (Calpe of the same). 

 The two swimming bells of very different size, the anterior much 

 the smaller. The bracts cover the members of the groups imper- 

 fectly, are massive, and have a cavity communicating with the 

 stem. 



Sp. AlyU pentagona ESCHSCH., KOELLIKER Die Siph. v. Mess. s. 4146, 

 Tab. X. ; here the single polyps have no covers : see a complete specimen 

 described and figured in LEUCKART Zool. Untersuch., i. s. 5661, Taf. nr. 

 fig. i 10. The bracts, or covers, which are not visible on the polyps at 



1 Compare also on this genus LESSON Centurie Zoologique, 1830, p. 161 183, 



PL 5557- 



